1. Field of the Invention
The invention relates to a semiconductor device and a method of assembling the same. More specifically, the invention relates to a semiconductor device having an FCBGA (flip chip ball grid array) package with a decoupling capacitor and a method of assembling the same. The semiconductor device and the assembling method are intended for use with DRAM-mixed system LSI and networking system LSI, for example.
2. Description of the Related Art
FIG. 6 is a cross-sectional view schematically showing an example of a conventional semiconductor device having an FCBGA package.
In the conventional semiconductor device, through-hole wires 61 are formed in a package board 60 of the FCBGA package. The through-hole wires 61 connect an upper surface to a back surface of the package board 60. Solder balls 62 are formed in a pattern of ball grid array (BGA) on the back surface of the package board 60. A semiconductor chip (die) 63 is flipchip-connected to the package board 60 in a manner that the semiconductor chip 63 is provided at a central region of the upper surface of the package board 60. A resin 64 is filled and cured between the package board 60 and the semiconductor chip 63. A spacer (stiffener) 65 is provided on the package board 60 to surround the periphery of the semiconductor chip 63. The spacer 65 is adhered to the package board 60 by an adhesive 66. A heat spreader/cover plate 67 is provided on the spacer 65 and the semiconductor chip 63 and adhered thereto. The heat spreader/cover plate 67 is formed of, for example, a Cu plate. The semiconductor chip 63 and the cover plate 67 are adhered together by a thermal paste 68, and the spacer 65 and the cover plate 67 are adhered together by an adhesive 66.
In general, when a semiconductor device of such a of type as above-described is mounted on a wiring board of application products, decoupling capacitors (not shown) for stabilizing power supply voltage are provided near a BGA (ball grid array) of an FCBGA package to enhance the signal integrity of the semiconductor device. It is preferable that the decoupling capacitors be provided near power supply lines. However, in the FCBGA package, outer lead balls OLB are provided in the BGA region, so that the decoupling capacitors cannot be provided near the power supply lines.
It is contemplated that the decoupling capacitors are provided at the central region of the BGA, without providing the outer lead balls at the central region. A microprocessor considered to have such a structure is disclosed in, for example, an Intel(R) Internet homepage, website hyperlink symbology omitted: Products and Supports—Intel(R) Pentium(R) 4 Processor. However, this structure limits the BGA disposition.
As described above, there is a problem with the conventional semiconductor device having the FCBGA package in that the decoupling capacitors cannot be provided near power-supply terminals, so that the signal integrity cannot be sufficiently enhanced. Also in the structure having the decoupling capacitors provided at the central region of the ball grid array, without disposing the outer lead balls at the central region, there arises the problem of limiting the BGA disposition.